Flexible rule



1927 R. s. BURDETTE FLEXIBLE RULE Filed June 26, 1925 INVENTOR F/cfiard .5 Burdeffe BY v ATTORNEY Pa ten ted F 8, 1927- araum -go STATES PATEN OFFICE.

RICHARD s. BURDETTE, or AKRON, OHIO.

FLEXIBLE RULE.

Application filed June 26, 1923. Serial No. 647,872. 1

My invention relates broadly to means senting-one form which my invention may for drawing any desired form of irregularly assume; curved lines with precision. More speclfi- Fig. 2 is a cross-sectional view of the struccally, my invention relates to a novel type of ture illustrated in Fig. 1, the section being flexible rule which embodies a high degree taken along the line 1l-1I thereof; of resiliency as well as a high degree of Fig. 3 is aview partiallyii elevation and rigidity of form, and which is inextensible. partially in section of a flexible rule repre- One "object of my invention consists in :s entmg another form which my invention providing a relatively inexpensive, durable may assume; flexible rule, which shall be adaptable to any Fig. 4 is a cross-sectional view of the rule curve of any shape whatsoever. Another illustrated in Fig. 3, the section being taken I object of my invention is to provide a fiexalong the line IV -1V thereof; and ible rule which shall embody rigidity of Fig. 5 is a view in elevation of a rule form, inextensibility, and asmooth drawing of the type illustrated in Figs. .3 and at surface. Other and ancillary objects are shaped to conform to an irregular curve. pointed out in the following description of As illustrated in Fig. 1 and 2, my rule my invention. comprises a body (3 of resilient rubber of the Heretofore, various types of irregular desired form, which is preferably a relacurve members have been employed for tively long flat member, which may be drawing irregularly curved lines among calibrated adjacent one edge thereof in any which are the rigid celluloid or steel curve desired manner. A sinuously curved remembers, sometimes known as French silient member-'8, preferably of spring steel, curves, and the flexible curve members havis centrally embedded within the rubber ing embedded therein a lead, soft copper, or body 6. The separate convolutions of the other plastic non-resilient metal strip. The member 8 are all of equal dimensions and rigid curve members are'objectionable beare in alignment. The rubber body 6, comcause it is necessary to have a set of several posed of raw rubber, with the member 8 thereof to meet the requirements of many embedded therein, is placed in a mold and irregular curves, and, at best, requires conis vulcanized. siderable trying and fitting to find the proper curve member and the proper portion to present a smooth surface ofl'ering but thereof to employ. having embedded therein a plastic metal pencil or pen in contact therewith. The rubmember are objectionable on account of her body 6 and the embedded member 8, be-

their relatively high cost, in addition to the ing both resilient, permit the member to be fact that their life of service is relatively bent to any desired shape or contour in one short. This is caused by the fact that the or more planes for drawing curves therelead, or other plastic metal employed therewith. The resiliency of the member causes in, breaks after being bent but a relatively it to regain its original shape on being refew times. Since frequent bending is absoleased. The spring member 8 which is comlutely essential in this type of device, its posed of relatively light wire serves to add life of service is of but short duration. rigidity to the rubber body of the rule By my invention I have provided a device without materially altering the flexibility which avoids the objection of being rigid, but thereof. This springmember may be bent is sufliciently firm to permit drawing a perto any desired configuration and serves to fectly smooth curve even when pressure is prevent buckling of the rubber body 6, exerted thereagainst. Also, a device con when bent to a curve of very small radius, tructed in accordance with my invention is which would otherwise occur. Also, it inexpensive, durable and not readily de causes the rubber to firmly resist deflection formed. under pressure exerted thereagainst by a For a more accurate description of my pencil. This permits the user to trace and invention, reference may now be had to the retrace a line as often as may be desired accompanying drawings of which: without forming more than a single narrow Fig. 1 is a view partially in elevation and line. partially in section of a flexible rule repre- The structure lllnstrated in Figs. 3, 4 and The fact that the rubber is cured causes it 5 The flexible members very little resistance to the movement of a lllll 5 differs from that shown in Figs. 1 and 2 by the addition of a reinforcing member 9,

herein illustrated as a steel wire which is- "through the convolutions of the wire 8 but maybe disposed entirely on one side thereof, the essential feature being that it reinforc-es the member in a longitudinal direction.

When the rule is bent, as illustrated in Fig. 5, the convolutions of the wire 8 adjacent one side of the rule move farther apart and the convolutions adjacent the opposite side move closer, together but the central portions thereof are held in a substantially fixed relationship by the inextensible wire 9.

In using the rule, it is bent to any desired angle or contour and is held in that osition while the curve is drawn. On releasing it, it immediately regains its original sha e. I

If desired, the rule may be provided with a beveled edge, which may, in some instances, be conducive to greater accuracy, but preferably, the edge is square. The advantage obtained by having the edge square is that the curved ends of the convolutions of the member 8 may extend into very close proximity to a square edge, but, on account of the reduction in thickness adjacent a beveled edge, the reinforcing wire may not extendinto close proximity thereto.

The reinforcing members herein referred to as metallic wires, steel wires, etc., may be composed of steel, brass or any other desired metal, but steel wire plated with brass is believed to be the most desirable. The steel wire is most suitable on account of its great strength and resiliency. The brass plating thereon is preferable because rubber, when vulcanized in'contact with brass or a brass plated object, forms a bond therewith which is greatly superior to that similarly formed with any other of the. ordinary metals. 'Ihese wires may be of any desired cross-section which will not interfere with the flexibility of the rule.

Thus, from the foregoing description, it will be apparent that I have provided a flexible rule capable of being used to draw any irregular curve in either one or more planes, Also, being inextensible, owing to the incorporation of the wire 9, it may be used for accurate measurement of surfaces other than flat. Also, the simplicity of the device renders it inexpensive to manufacture, and with the wires 8 and 9 concealed within the molded rubber body presents apleasing appearance. Ri 'dity, without the loss of flexibility or re si ience, is rovided by the numerous points at whic the ruler edge is reinforced by the member 8.

Although I have illustrated several forms which in invention may assume, and-have describe in detail the a plications thereof, it will be apparent to tli art that it is not so limited but that various modifications and changes may be made therein without departing from the spirit of my invention or the scope of the appended claims.

What I claim is:

. 1. A rule comprising a pliant body member having embedded therein a resilient metallic member of sinuous contour.

2. A rule comprising a vulcanized rubber body having embedded therein a substan tially longitudinally extending brass plated steel wire. 1

3. A rule comprising a rubber body having embedded therein a resilient metallic wire of sinuous contour, and a longitudinally disposed relatively straight flexible reinforcing member.

4. A rule comprising a relatively long flat rubber body having embedded therein a resilient metallic wire of sinuous contour disposed longitudinally thereof and a relatively straight wire interwoven with the sinuously curved wire and disposed longitudinally of the rule..

5. A rule comprising a relatively long flat rubber body having embedded therein a resilient metallic wire of sinuous contour, the individual convolutions of the wire being disposed at right angles to the longitudinal axis of the rule.

6. A rule comprising a relatively long flat rubber body having embedded therein a resilient metallic wire of sinuous contour, the individual convolutions of the wire being disposed at right angles to the longitudinal axis of the rule, and a. relatively straight wire interwoven with the sinuously curved wire and disposed longitudinally of the rule.

7. A rule comprising a relatively long flat rubber member so reinforced as to be adapt ed to be flexed in a pluralityof planes.

8. A member comprising a relatively long rubber body of relatively small cross sectiolu having a substantially longitudinally extending flexible metallic wire embedded therein.

9. A member comprising a relatively long rubber bed of relatively small cross-section, having em edded therein a longitudinally extending flexible metallic member of sinuous contour.

In witness whereof, I have hereunto signed my name.

RICHARD S. BURDETTE.

ose skilled in the 

